A serial bus system has been increasingly applied in automatization and manufacturing, where all the users are connected by a serial bus into a network, and data are exchanged over the bus in a master-slave mode. In the prior art, there is a bus station system with an integrated bus supervision control function as illustrated in FIG. 1, where the system includes bus monitors added respectively to a control unit, a gateway, an executor, and a sensor to supervise in real time the data over the bus. The system has the networks interconnected by the gateway, and the number of bus monitors makes the bus system too complex in structure, costly in hardware, and difficult to manage and maintain later.
The Ethernet and the Controller Area Network (CAN) bus remain the mostly widely applied at present, but they also suffer particularly from the following drawbacks:
1) Since the Ethernet operates with Carrier Sense Multiple Access with Collision Detection (CSMA/CD), if the network is heavily loaded (more than 40%), then the deterministic network may not accommodate required real-time industry control. For example, if a two-wire Ethernet transmission device communicates data with CSMA/CD, then the reliability of transmission in the system may be poor in this transmission mode.
2) The operating CAN bus is characterized in that the event trigger mechanism thereof causes events in the network to collide easily with each other, so that transmission over a channel may be subjected to an error and a jam, thus resulting in poor reliability of the system, and even if the collision can be resolved by arbitration, then data transmission at a low priority may not be real-time; and if master and slave stations operate, then the different stations in the distributed control system will need to be connected for communication, and one of the nodes will transmit information on its own initiative to the other nodes over the network at any instance of time without distinguishing the master station from the slave stations, so that the respective nodes communicating freely may occupy significant components of the channel, thus suppressing the transmission rate of the data over the channel, and degrading the performance of transmission.
At present, network transmission has been widespread all over the world, the security of transmit data influences directly the security of our working, living, and even nation, so it is highly desirable to provide a high-performance, highly reliable, and highly real-time industry internet communication system.